Means for reducing the reactance of electromagnetic devices for telephone-circuits.



y W. K. HOWE. MEANS FOR REDUCING THE REACTANGE OF ELECTROMAGNETIG DEVICES FOR TELEPHONE CIRCUITS. APPLICATION FILED APR.13,1909.

Patented Sept. 21, 1909.

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Specification of Letters Patent. Pgtgmfiwdl Search 231, 11 9:1139,

Application filed April 13, 1905. Serial No. 489,742.

To all whom it may concern:

Be it known that I, Vt INrHRoP K. Howe, a citizen of the United States, and resldent of Rochester, in the county of Monroe and 1 State of New York, have invented certain newand useful Improvements in Means for Reducing the Reactance of Electromagnetic Devices for Telephone-Circuits, of which the following is a specification.

This invention relates to means for re ducing the reactance of electromagnetic devices in telephone circuits.

The invention consists in the apparatus hereinafter described and claimed.

In the -drawings:Figure l is an elevation of a pair of electromagnets, one of which is shown in vertical section, embodying th s invention; and Fig. 2 is a diagram of an apparatus in which this invention 1s employed in connection with a telephone circuit.

In Fig. 1 is shown an electromagnet having the windings 1, and the usual iron cores 2. 3 isthe yoke connecting the cores of the two magnets, and 4 represents a movable armature. In a manner that is common, the ends of the coil 1 may have insulating disks 5. Around the core 2 and between it and the wire winding 1, a tubular copper sheath- 6 is introduced, whereby the reactance of the circuit, of which the Winding 1 forms a part, is decreased, or, in other words, the electroma net is made substantially or largely noninductive.

In Fig. 2, the invention is shown in. connection with a telephone circuit, and two stations A and B are indicated in the diagram, which, of course, may be separated at any suitable distance. At each station is the noninductive relay 10 of the character above described. This relay is inserted in the two lines 11 and 12 of the telephone circuit 1. Each of these two lines runs through one coil of each of the relays 10, and the other of said two lines runs through the other coil thereof, for the purpose of keeping the lines in balance for telephoning purposes. At the ends of the lines 11 and 12 are reactance coils 13, having a suflicient-ly high reactance to prevent the telephone ciu'rent from being shunted through them. A line battery 14 sheath immediately around connects ground and one of the reactance coils 13, and the other reactance coil is connected with the ground. A key is provided at each station for breaking the circuit simultaneously in both of the lines 11 and 12, whereby the circuit through both coils of the relays 10 is uninterrupted. Each relay 10 controls a local circuit 16, including a local battery 17, and a translating. device 18. This translating device in the present instance is indicated as an electromagnet having an armature which may be used for signaling purposes, and for which other forms of electromagnetic signaling devices may be employed. At each station is a telephone outfit 19 including the usual elements thereof, which is arranged as usual in connection with the lines 11 and 12. i

The operation of the deviceis as follows: For signalingpurposes a key 15 is opened. and closed in any desired manner, and in response the translating devices 18 are operated. If a sounder is used as the translating device, telegraphing maybe carried on over the line. The translating device may be employed as a call for telephone phi-poses, and the call may be effected by operating the key 15, whereupon the operators at the calling and the called stations may make use of their telephones 19.

By means of the noninductive relay. or electromagnetic devices herein set forth, the employment of theordinary direct current for energizing the relays 10 is made possible without interfering with the use of the telephones on the same circuit. By this means an electromagnetic device may be introduced into the telephone circuit without creating detrimental. impedance to the talking current.

it is obvious that the relay 10 may be used directly as a translating device without the employment of a secondary circuit with its devices, in all cases where the-power of the relay 10 is suflicient to accomplish the desired action.

What I claim is 7 1. The combination of a telephone circuit, telephones in the circuit, an electromagnetic device in said circuit havinga. tubular copper its-core, a source of current for energizing the electromagnetic l a tubular copper sheath immediately around 1.0

device, and .means in the circuit for controlthe core of each coil, and a source of current ling the electromagnetic device. connected with said telephone circuit for 2. The combination ofla two-Wire teled energizing the electromagnetic device.

phone circuit, a series of te ephones conneete With the tWo Wires of the circuit, a series of WINTHROP HOWE" keys for making and breaking both lines of I Vitnesses: said circuit, an electromagnetic device hav- F. L. DonGsoN, ing two coils one in each of said lines and W. A. JACKSON. 

